I have one Butterfly dress by Bettie Page Clothing, which is about a size 18 (the label is XXXL, but it runs small, so is equivalent to their usual XXL).
It's a really gorgeous dress and perfect for summer in a lovely white cotton with red butterfly print. It's lined with cotton and has a built-in cotton underskirt. The hem of the dress has lovely red embroidery. All this for £65.